I had two different lefty bassists in my band. me being (at the time) a lefty guitar player that made for a pretty weird stage presence.
I remember when I was a pre-schooler I'd go to this lady's house until my parents would come home. kinda like a baby sitter for a couple of hours. and one day the subject came up and I didn't know whether I was lefty or righty so she handed me a marker and told me to "pretend" I'm writing my name. this didn't came a surprise to no one since my mom is also left handed.
my sister used to say I was just imitating her, and that handedness was just a "choice".
I suck at almost any sport, I have a stronger right leg but it's kinda retarded so I learn stuff with my left leg and later execute them with right. which made playing soccer a weird a-tick-and-a-tock kinda process.
the only sport where I wasn't horrible was mui-thai, and I have to admit the being a lefty there was an enormous advantage. not only as a lefty I have a significantly stronger weak hand than most righties, (which means I can fight in both stances) righties usually have a hard time getting used to fighting a south paw while I'm pretty used to fighting them.
in music, I tried learning guitar righty but I sucked big time. I could barely finger an E minor.
so I moved on to a lefty. later I had my teacher (who also sold guitars) restring one of his cheaper models upside down. it was still there lefty strung (over a decade now) when I last visited him.
and we have allot of true lefty kids in the area now, ( a hell of allot more than when I was a kid) I'm pretty sure it has something to do with that green cheapo no brand strat. and my pseudo-local-legend hard core band I played with at the time. seeing someone do it makes it a more comfortable choice.
"Again the Israelites cried out to the LORD, ahd he gave them a deliverer, Ehud, a left handed man..."
public schools in Israel teach the old testimony, and this is pretty much the coolest tale we were taught. aside from the whole double edged sword and what the hebrew word "parshedona" means. the story tells that Eglons guards only checked for weapons on the left leg, so ehuds sword which was carried lefty on his right leg went unnoticed.